Valve for steam-engines



(No Model.)

2 Sheets-Sheet 1-.

S. T. WILLIAMS. VALVE FOR STEAM ENGINES.-

Patented June 17', 1890.

2 Sheets-Sheet 2.

(No Model.)

B .m G MN n M LA um WS R .0 P. L A V Patented June 17; 1890.

NITED STATES SAMUEL T. \VILLIAMS, OF BALTIMORE, MARYLAND.

VALVE FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 430,160, dated June 17, 1890. Application filed October 15, 1889. Serial No. 327,072. (No model.)

To all whom it may concern.-

Be it known that 1, SAMUEL T. WILLIAMS, of Baltimore, in the State of Maryland, have invented certain new and useful Improvements in Valves for Steam-Engines, which improvements are described in the following specification, and are illustrated by the accompanying drawings.

My invention is a balanced slide-valve, including a pressureplate, which holds the valve to its seat, and a system of guides, which limit and direct the movement of the pressure-plate.

The best mode in which I have contemplated applying the principle of my invention is shown in said drawings, in which Figure 1 is a central vertical longitudinal section of a valve-chamber and contents, including a valve, a pressure-plate, and other mechanism, all of which are constructed in accordance with my invention. The plane of section of this view is parallel to the vertical plane, in which lies the axis of the steamcylinder of the engine to which my invention is applied. Fig. 2 is an end view of the same, a part of the casing of the valve-chamber be ing removed and a part of the steam-cylinder being shown in position. Fig. 3 is a plan View of the same, the cover of the valvechamber being removed. Fig. 4 is an edge view of the cover of the valve-chamber. Fig. 5 is a plan view of the valve.

In the views the numerals 1, 2, 3, and 4 denote, respectively, the tour side walls of the valve-chamber. Wall 2 is perforated by a large hole 8 for the escape of the exhauststeam, as seen in Fig. 1. Theinteriormiddle portion of the bottom 5 of said chamber is converted into a fiat valve-seat 6 and has three openings-namely, a large central port 7 for the admission of steam from the boiler to the valve, and two steam and exhaust ports 9 and 10, located one upon either side of the port 7 and leading to the ends of the cylinder.

Valve 11 (seen in detail 'in Fig. 5) is a fiat cast-iron plate planed on both sides and provided with a central port 12 and with two lateral ports 13 and 14. Said valve is also provided with a stem 15, which works through the stufling-box 16, fastened to wall 1. Stem 15 is provided with a head or nut 17, which is held loosely to valve 11 by means of two recessed lugs 18, cast upon the edge of said valve. The pressure-plate 19. contiguous to valve 11, is an iron casting of irregular form. The lower portion or base of this plate, as seen in a plan view, Fig. 3, is nearly square, while the upper portion is a hollow cylinder. The under side of plate 19, next to valve 11, is provided with a central recess 20 and two lateral recesses 21 to correspond with the described ports in the valve-seat. Each of those two opposite vertical sides of plate 19, which stand, respectively, adjacent to sides 1 and 3 of the valve-chamber, is provided with an outwardly-projectiug inclined tongue or wing 22. These tongues are V- shaped in cross-section, as seen in Fig. 1, and lie parallel to each other, as seen in Fig. 3. The inclination of these tongues corresponds with that of the V-grooves,which they occupy, as hereinafter described. A screw 31, provided with a jam-nut, is set in the side wall 2 in a position to act upon plate 19, as seen in Figs. 2 and 3. The upper hollow cylindrical portion of the pressure-plate 19 is partly occupied by a relief-plate 23. This plate consists of a circular disk, which is provided with a circumferential flange 24. By means of a packing-rin g 25, which is sprung into a groove in flange 24, plate 23 is fitted closely into the top of the pressure-plate 19. A pin 26 is secured in the center of the relief-plate 23, and extends downward through a hole in the middle portion of the pressure-plate 19. Upon pin 26 and between plates 19 and 23 is placed a coil-spring 27. The valve-chamber is closed by a cover 28, which is fastened on by bolts. This cover, which is seen in detail in Fig. 4, is provided with two dependent arms 29, having V-grooves, which are occupied by tongues 22. These grooves are placed at an angle with the plane of the valve-seat, as indicated in Fig. 2. This angle is preferably about forty-five degrees. That area of the pressureplate which is exposed to downward steampressure slightly exceeds that area of the same which is exposed to upward steam-press ure. The remaining particularsof construction of my invention will sufficiently appear from the drawings and from the mode of operation.

The general mode of operation of my invention is obvious and requires no description. Certain particulars, however, may be observed. The excess of downward steampressure upon plate 19, resulting from the relative extent of the exposed areas above described, tends to hold that plate down upon the valve. Spring 27 conspires to produce the same result. Under normal conditions the pressure-plate is held down by these forces; butif water should accumulate in the cylinder the valve and pressure-plate rise and let the water out into the exhaust. When steam is shut off, the spring holds the pressure-plate and relief-plate apart and so prevents hammering. The tongues 22, being inserted in inclined grooves, as described, impart steadiness to the pressure-plate and prevent it from tipping up or down at either edge as the. valve advances and recedes. Screw 29 may be used or disused at pleasure. The function of this screw when used is to remove the pressure of plate 19 from the valve by forcing that plate slightly upward in the course which is determined by said grooves and tongues 22. This diminishes wear and leaves the valve balanced between the steam-pressure above and below it.

Such being the construction and operation of my invention, 1 claim 1.. A slide-valve and a superimposed pressure-plate, in combination with a relief-plate which is set in the back of the pressure-plate, substantially as and for the purpose specified.

2. In a'valve-chamber, a fiat slide-valve, a pressure-plate which is provided with guidin g-tongues, moving in grooves which are provided therefor, in combination with a movable relief-plate which is set steam-tight in the back of said pressure-plate, substantially as and for the purpose specified.

3. In avalve-chamber, a slide-valve, a pressure plate which is provided with lateral tongues fitted into grooves, and a relief-plate set in the back of said pressure-plate, in combination with a spring pressing the pressureplate toward said valve, substantially as and for the purpose specified.

4. A slide-valve, a pressure-plate which is provided with oblique lateral tongues occupying grooves which are provided therefor, and an adj Listing-screw acting upon said pressureplate, in combination with a relief-plate which is set in the back of said pressure-plate, substantially as and for the purpose specified.

5. A slide-valve, a pressure-plate which is provided with oblique lateral tongues occupying grooves which are provided therefor, an adjusting-screw acting upon said pressureplate, and a relief-plate which is set in the back of said pressure-plate, in combination with a spring between said relief-plate and the body of said pressure-plate, substantially as and for the purpose specified.

In testimony whereof I hereunto set my name in the presence of two witnesses.

SAMUEL T. WILLIAMS.

Witnesses:

THos. KELL BRADFORD, RICHARD H. MATHER. 

